1. 1 VINI: Virtual Network Infrastructure Jennifer Rexford Princeton University http://www.cs.princeton.edu/~jrex

2. 2 The Internet: A Remarkable Story Tremendous success –From research experiment to global communications infrastructure The brilliance of under-specifying –Best-effort packet delivery service –Key functionality at programmable end hosts Enabled massive growth and innovation –Ease of adding hosts and link technologies –Ease of adding services (Web, P2P, VoIP, …) But, change is easy only at the edge… 

3. 3 Rethinking the Network Architecture But, the Internet is showing signs of age –Security, mobility, availability, manageability, … Challenges rooted in early design decisions –Weak notion of identity, tying address & location –Not just a matter of redesigning a single protocol Revisit definition and placement of function –What are the types of nodes in the system? –What are their powers and limitations? –What information do they exchange?

4. 4 Hurdle #1: Deployment Dilemma An unfortunate catch-22 –Must deploy an idea to demonstrate feasibility –Can’t get an undemonstrated idea deployed A corollary: the testbed dilemma –Production network: real users, but can’t change –Research testbed: easy changes, but no users Bad for the research community –Good ideas sit on the shelf –Promising ideas do not grow up into good ones

5. 5 Hurdle #2: Too Many Design Goals Many different system-engineering goals –Scalability, reliability, security, privacy, robustness, performance guarantees, … –Perhaps we cannot satisfy all of them at once Applications have different priorities –Online banking: security –Web surfing: privacy, high throughput –Voice and gaming: low delay and loss Compromise solution isn’t good for anyone

6. 6 Hurdle #3: Coordination Constraint Difficult to deploy end-to-end services –Benefits only when most networks deploy –No single network wants to deploy first Many deployment failures –QoS, IP multicast, secure routing, IPv6,… –Despite solving real, pressing problems Increasing commoditization of ISPs senderreceiver 123

7. 7 Virtualization to the Rescue Multiple customized architectures in parallel –Multiple logical routers on a single platform –Isolation of resources, like CPU and bandwidth –Programmability for customizing each “slice”

8. 8 Overcoming the Hurdles Deployment Dilemma –Run multiple experimental networks in parallel –Some are mature, offering services to users –Isolated from others that are works in progress Too Many Design Goals –Run multiple operational networks in parallel –Customized to certain applications and users Coordination Constraint –Run multiple end-to-end services in parallel –Over equipment owned by different parties

9. 9 Three Projects: GENI, VINI, CABO Global Environment for Network Innovations –Large initiative for a shared experimental facility –Jointly between NSF CISE division & community –Distributed systems, wireless, optics, backbone VIrtual Network Infrastructure –Baby step toward the design of GENI –Systems research on network virtualization Concurrent Architectures Better than One –Clean-slate architecture based on virtualization –Economic refactoring for end-to-end services See http://www.geni.net and http://www.vini-veritas.net

10. 10 VINI: VIrtual Network Infrastructure

11. 11 VINI Offers “Controlled Realism” Start with a controlled experiment Relax constraints, study effects Result: an operational virtual network that’s –Feasible –Valuable –Robust –Scalable, etc. Topology Actual network Arbitrary, emulated Traffic Real clients, servers Synthetic or traces Traffic Real clients, servers Synthetic or traces Network Events Observed in operational network Inject faults, anomalies

12. 12 Fixed Infrastructure Deployed VINI nodes in National Lambda Rail and Abilene, and PoPs in Seattle and Virginia

13. 13 Shared Infrastructure Experiments given illusion of dedicated hardware

14. 14 Flexible Topology VINI supports arbitrary virtual topologies

15. 15 Network Events VINI exposes, can inject network failures

16. 16 External Connectivity s c Experiments can carry traffic for real end-users

17. 17 External Routing Adjacencies s c BGP Experiments can participate in Internet routing

18. 18 VINI Platform Design

19. 19 Virtualizing the Computer Starting with the PlanetLab software –Each experiment has its own virtual machine –Each has “root” in its own VM, can customize –Reserve processing resources per VM Virtual Machine Monitor (VMM) (Linux++) Node Mgr Local Admin VM 1 VM 2 VM n … PlanetLab node

20. 20 Creating the Virtual Topology Goal: real routing protocols on virtual network topologies Various routing protocols (BGP, OSPF, RIP, IP multicast) Run unmodified routing software in a virtual machine XORP (routing protocols) VM

21. 21 Virtual Network Abstraction PlanetLab limitation: –Does not virtualize the underlying network For each VM we want –Interfaces, bound to tunnels to other nodes –Networking stack (e.g., forwarding table) –Packet forwarding in OS Across VMs we want –Independent topologies –Resource isolation XORP (routing protocols) eth1eth3eth2eth0 FIB Control Data User space OS tunnels

22. 22 Network Name Spaces (NetNS) NetNS extension to Linux –Virtualizes the network stack –Each network stack bound to user process(es) Provides us with –Separate forwarding table (FIB) –Separate interfaces But, a few challenges remain –Connecting interfaces to tunnels –Supporting non-IP protocols –Providing isolation between virtual nodes

23. 23 Connecting Interfaces to Tunnels Ethernet switch –Linux bridge module –Connects all interfaces –And all tunnels Short bridge –No MAC learning –No forwarding look-up –No frame header copying EGRE tunnels –Carry Ethernet frames –Support non-IP protocols XORP (routing protocols) eth1eth3eth2eth0 Short Bridge etun3 etun2 etun1 FIB User space OS

24. 24 Isolation Between Virtual Networks Virtual host (user space) –Experimenter’s software –Protocols, applications Virtual host (OS) –Forwarding tables –Virtual Ethernet interfaces Shared substrate (OS) –Tunnels between nodes –Enforcing rate limits XORP (routing protocols) eth1eth3eth2eth0 Short Bridge etun3 etun2 etun1 FIB User space OS

25. 25 Ongoing Work on Packet Forwarding Tension between three goals –High-speed packet forwarding –Customization of the data plane –Sharing of the data plane Step #1: Greater flexibility –Customized data planes in the kernel –Virtualizing Click to support different virtual hosts Step #2: Greater speed –Customized data planes in an FPGA –Virtualizing the NetFPGA board from Stanford

26. 26 Example Experiment on VINI

27. 27 Intra-domain Route Changes s c 1176 587 846 260 700 639 1295 2095 902 548 233 1893 366 Watch OSPF route convergence on Abilene 856

28. 28 Ping During Link Failure Link downLink up Routes converging Abilene RTT: 73ms

29. 29 TCP Throughput Zoom in Link downLink up

30. 30 Arriving TCP Packets Slow start Retransmit lost packet VINI enables a virtual network to behave like a real network

31. 31 Other Example VINI Experiments Scaling Ethernet to a large enterprise Routing-protocol support for mobile hosts Network-layer support for overlay services Piggybacking diagnostic data on packets Multiple solutions to multiple problems…

32. 32 Where does all this experimentation lead us?

33. 33 The Case for Pluralism Suppose we can break down the barriers… –Enable realistic evaluation of new ideas –Overcome the coordination constraint Maybe there isn’t just one right answer –Maybe the problem is over-constrained –Too many goals, some of them conflicting Maybe the goals change over time –And we’ll always be reinventing ourselves –The only constant is change So, perhaps we should design for change

34. 34 Different Services, Different Goals Performance –Low delay/jitter: VoIP and online gaming –High throughput: bulk file transfer Security/privacy –High security: online banking and e-commerce –High privacy: Web surfing Scalability –Very scalable: global Internet reachability –Not so scalable: communication in small groups

35. 35 Applications Within an Single ISP Customized virtual networks –Security for online banking –Fast-convergence for VoIP and gaming –Specialized handling of suspicious traffic Testing and deploying new protocols –Evaluate on a separate virtual network –Rather than in a dedicated test lab –Large scale and early-adopter traffic Leasing virtual components to others –ISPs have unused node and link capacity –Can allow others to construct services on top

36. 36 Economic Refactoring in CABO Infrastructure providers: Maintain routers, links, data centers, and other physical infrastructure Service providers: Offer end-to-end services (e.g., layer 3 VPNs, SLAs, etc.) to users Infrastructure ProvidersService Providers Today: ISPs try to play both roles, and cannot offer end-to-end services

37. 37 Similar Trends in Other Industries Commercial aviation –Infrastructure providers: Airports –Infrastructure: Gates, “hands and eyes” support –Service providers: Airlines E.g.: airplanes, auto industry, and commercial real estate PEK ATL JFK SFO

38. 38 Communications Networks, Too! Two commercial examples in IP networks –Packet Fabric: share routers at exchange points –FON: resells users’ wireless Internet connectivity FON economic refactoring –Infrastructure providers: Buy upstream connectivity –Service provider: FON as the broker (www.fon.com) Broker

39. 39 Enabling End-to-End Services Secure routing protocols Multi-provider Virtual Private Networks Paths with end-to-end performance guarantees Today Cabo Competing ISPs with different goals must coordinate Single service provider controls end-to-end path

40. 40 Conclusion The Internet needs to change –Security, mobility, availability, management, … We can overcome barriers to change –Enable realistic experimentation with new ideas –Enable multiple designs with different trade-offs –Enable end-to-end deployment of new services Network virtualization is the key –Run many research experiments in parallel –Offer customized end-to-end services in parallel VINI as an enabling experimental platform